Nearly 4 week old chicks eating pine chips, is this 'normal'

I put new pine chips in the brooder today and the chicks are eating it, they have eatin it in the past, but not like this. They have there crumble and water, so I am not sure why they have taken a fancy to this???

I've got 75 3 week olds and about 40 of them love eating the shavings. They don't get the big pcs, just those little trailing off the cut.

they suck them down like candy to a kid, none have croaked over dead so I don't think it hurts them. They've been doing it since day
3 so if it was a problem I'd have seen it by now. Chopped up a boiled egg last night and put in there, they ran from it like it was going
to eat them. Left it over night, they warmed up to it sometime in the might and devoured it.

I look at it like this. They might find little pcs in nature, or a leaf. If it's interesting to them, they'll eat it. If all the chickens over the last
century died from eating junk, we wouldn't have chickens now.

Mine shyed away from the eggs and yogurt the first time I gave it to them, they RAN for cover. But now they actually will knock the bowl out of my hand if I don't have a good grip on it just to get to eitether the eggs or the yogurt, they are CrAzY over both of them.

I raise more than 700 chicks a year and I no longer use shavings.
I had so many losses due to chicks being on shavings that I finally went to using the woven nylon feed bags. They are not the slippery commercial kind. They are bags I get from our local feed mill and are "rough" enough for chicks to stand on. I have not had a spraddle leg chick in more than a year.
And since I changed to bags, I do not have chick deaths. However, I also roll up the bags every day and put clean ones down.

What you may want to do is dig up grass clumps with the dirt attached and let them have it every day.